Field of the Invention
Embodiments of the present invention relate generally to articles of footwear; and more specifically to an upper with an inflation system, and footwear and methods of manufacturing that include the upper.
Background Art
Individuals are often concerned with the amount of cushioning and the fit an article of footwear provides. This is true for articles of footwear worn for non-performance activities, such as a leisurely stroll, and for performance activities, such as running, because throughout the course of an average day, the feet and legs of an individual are subjected to substantial impact forces. When an article of footwear contacts a surface, considerable forces may act on the article of footwear and, correspondingly, the wearer's foot. The sole functions, in part, to cushion the wearer's foot and protect it from these forces. To achieve adequate cushioning, many footwear soles are relatively thick and heavy. When sole size and/or weight are reduced to achieve other performance goals, protection of the wearer's foot is often compromised.
Although the human foot possesses natural cushioning and rebounding characteristics, the foot alone is incapable of effectively overcoming many of the forces encountered during every-day activity. Unless an individual is wearing shoes that fit properly and provide proper cushioning and support, the soreness and fatigue associated with every-day activity is more acute, and its onset accelerated. The discomfort for the wearer that results may diminish the incentive for further activity. Equally important, inadequately cushioned and improperly fit footwear can lead to injuries such as blisters; muscle, tendon and ligament damage; and bone stress fractures improper footwear can also lead to other ailments, including back pain.
Proper footwear should complement the natural functionality of the foot, in part, by incorporating a sole (typically including an outsole, midsole and insole) and/or an upper which absorbs shocks and provides appropriate cushioning. Therefore, a continuing need exists for innovations in providing cushioning to articles of footwear. Furthermore, because the desired fit provided by an article of footwear differs for various individuals and activities, there is a need for innovations related to customized and/or tunable fit in articles of footwear.